<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div class="app">
        <ul>
            <li v-for="(item,index) in arr">{{index+1}}{{item}}</li>
        </ul>
        <button @click="add">点击增加</button>
        <button @click="remove">点击移出</button>
    </div>
    <script src="../vue.js"></script>
    <script>
        const vm = new Vue({
            el: ".app",
            data: {
                arr: ["大象", "老虎", "熊猫", "狮子"]
            },
            methods: {
                add() {
                    this.arr.push("鱼")
                },
                remove() {
                    this.arr.shift()
                }
            }
        })
    </script>
</body>

</html>